Saxon

I'm encountering the next NPE when running an XSLT transformation that has the schema based validation feature activated.

java.lang.NullPointerException
        at com.saxonica.ee.schema.sdoc.XSDAttributeGroup.checkImmediateRedefinition(XSDAttributeGroup.java:321)
        at com.saxonica.ee.schema.sdoc.XSDAttributeGroup.patchUpSelfReferences(XSDAttributeGroup.java:298)
        at com.saxonica.ee.schema.sdoc.XSDAttributeGroup.postValidate(XSDAttributeGroup.java:244)
        at com.saxonica.ee.schema.sdoc.SchemaElement.validateSubtree(SchemaElement.java:192)
        at com.saxonica.ee.schema.sdoc.SchemaElement.validateChildren(SchemaElement.java:229)
        at com.saxonica.ee.schema.sdoc.SchemaElement.validateSubtree(SchemaElement.java:191)
        at com.saxonica.ee.schema.sdoc.XSDSchema.validateChildren(XSDSchema.java:435)
        at com.saxonica.ee.schema.sdoc.SchemaElement.validateSubtree(SchemaElement.java:191)
        at com.saxonica.ee.schema.sdoc.SchemaReader.read(SchemaReader.java:158)
        at com.saxonica.ee.schema.SchemaCompiler.readSchema(SchemaCompiler.java:347)
        at com.saxonica.config.EnterpriseConfiguration.readSchema(EnterpriseConfiguration.java:447)
        at com.saxonica.ee.validate.XSIAttributeHandler.loadSchema(XSIAttributeHandler.java:363)
        at com.saxonica.ee.validate.XSIAttributeHandler.processXsiNoNamespaceSchemaLocation(XSIAttributeHandler.java:214)
        at com.saxonica.ee.validate.XSIAttributeHandler.startElement(XSIAttributeHandler.java:82)
        at net.sf.saxon.event.StartTagBuffer.startContent(StartTagBuffer.java:220)
        at net.sf.saxon.event.ProxyReceiver.startContent(ProxyReceiver.java:178)
        at net.sf.saxon.event.ProxyReceiver.startContent(ProxyReceiver.java:178)
        at net.sf.saxon.event.ReceivingContentHandler.startElement(ReceivingContentHandler.java:356)
        at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:501)
        at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:400)
        at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl$NSContentDriver.scanRootElementHook(XMLNSDocumentScannerImpl.java:626)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:3104)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:921)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:647)
        at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:140)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:511)
        at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:808)
        at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
        at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:119)
        at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
        at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
        at net.sf.saxon.event.Sender.sendSAXSource(Sender.java:441)
        at net.sf.saxon.event.Sender.send(Sender.java:146)
        at net.sf.saxon.Controller.transform(Controller.java:1692)
        at net.sf.saxon.s9api.XsltTransformer.transform(XsltTransformer.java:547)
        at net.sf.saxon.Transform.processFile(Transform.java:1056)
        at net.sf.saxon.Transform.doTransform(Transform.java:659)
        at net.sf.saxon.Transform.main(Transform.java:80)
Fatal error during transformation: java.lang.NullPointerException:  (no message)

Unfortunately, I don't find an easy way to reproduce it, so I have attached all the resources that are needed to reproduce it.

From command line:

D:\workspace\eXml>java -Xmx60m -cp lib/saxon9ee.jar net.sf.saxon.Transform -xsl:final.xsl -s:dita_test.dita -val:lax